The present invention relates generally to lock devices and, more particularly, to a lock assembly with a key-activated removable core structure.
A cylinder lock comprises a central plug or core and an outer shell or housing, in which the core rotates. The housing is mounted in a suitable latch structure. A number of prior art disclosures describe devices intended to provide a removable core in a cylinder lock. The advantage of removable core locks is that they may be rapidly re-keyed by relatively unskilled personnel. Such re-keying may be required as a result of a potential security breach or occurring due to the loss or non-return of a key.
The patent publication U.S. Pat. No. 6,076,386 (Etchells et. al.) describes a removable core lock wherein a restraining member in the form of a ball is provided in a concentric groove formed onto a core housing. A drawback with that solution is the lack of code related blocking mechanism for the removal of the core.
A removable core lock for cars is disclosed in the patent publication U.S. Pat. No. 2,036,764, wherein the connection between the core and an adapter actuating the lock operating means is in the form of a bayonet joint releasable without tools. In order to operate the lock, a long user key engaging a groove in the adapter must be used to rotate not only the core but also the adapter. In order to disengage the core from the adapter, a short key is used, whereby the core is rotated 90 degrees relatively to the adapter in a specified direction.
While this latter solution provides for a simple design, it is accompanied by several drawbacks. Firstly, the rotation of the adapter relies on the strength of the key tip, resulting in an unreliable operation. Secondly, this lock is relatively easy to manipulate.
An object of the present invention is to provide a removable core lock wherein the drawbacks of prior art devices are eliminated or at least mitigated.
The invention is based on the realization that engagement elements can be used to selectively engage and disengage the rotation of a core relatively to an adapter in a removable core lock.
According to the invention there is provided a removable core lock and key and a service key as recited in the claims.
With the inventive device the above-mentioned drawbacks of prior art are eliminated or at least mitigated. The lock device according to the present invention as defined by the appended claims has a configuration wherein means of connection are provided to axially interlock the core and an adapter operatively connected to a bolt, nd wherein engagement elements are provided to allow or prevent the means of connection to be disengaged.
In a particularly preferred embodiment, the engagement elements comprise a radially moveable side bar in the core and a recess in an aperture in an adapter operatively connected to a bolt. The side bar provides a secure way of preventing rotation of the core relatively to the adapter. In a further preferred embodiment, a bayonet joint is used as the means of connection to prevent withdrawal of the core from the cylinder housing, providing a robust arrangement.
Further preferred features are defined in the dependent claims.